311 vs 300 sounds like a pea under a pretty tall stack of mattresses. I doubt most people could immediately tell a 15% difference in rates unless running them back-to-back. That is a 4% difference and may be less than the production tolerances.

 

What does that have to do with the price of tea in China?

The lightest front bar ever offered was '04-05 at 300 lb/in, lightest rear is 311 lb/in for '04-09' base. If the car is being run BStreet, only one bar can be changed, the front will be that bar obviously. The 300 lb/in comment was in reference to someone posting that the AP2 came with a 260 lb/in bar.

 

Are we really on 'street tires'? The 245/255 is only a tick behind the STR tire size and the tires are the same. The limit is that the bar only affects roll and front/rear roll bias by stiffening the front. STR can affect pitch and roll with adjustments at both ends.

That could make shocks important. Looking at SoloStorm output last weekend there was one section were there were left/right transitions at the rate of 7 every 10 seconds. But what that shock should look like and if it would still be reasonable on car that is also street driven.
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Nobody in STR is running a bar that large though. People used to stuff things like 275 wide Hoosiers on stock S2000 tires, and that's what those large bars were made for. Like you said, changing your roll bar stiffness is effectively changing your cars balance. In a perfect world, you probably wouldn't run any sway bar at all, and would tune your car with spring rates, but we happen to be in a class where that isn't possible. We put as much tire (grip) on the front of the car as possible, and then the rear end becomes loose. That's where the beefy front sway bar comes in to play. With the 245/255 combo, you are increasing front contact patch by 14% and rear by only 4%, so it's going to become loose. So you stiffen the front to balance it out. If you are pushing, you went too far, unless there are gains to be made in front grip via camber, toe, caster, or *shock*.

But on the subject of shocks, it's my personal opinion that the stock shocks are the last thing you should invest in for an S2000 in B Street. After all, a car from our region made it to 2nd in nationals last year on stock shocks with over 100,000 miles on them. On top of that, the cost of a shocks that are worth investing in, are equal to the cost of every other B Street mod combined. Until you are that fast, there are better places to spend your money.
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A bar how big? Everyone I know in STR is running a bar similar to the Gendron or Saner in stiffness in the front.

 

Are we really on 'street tires'? The 245/255 is only a tick behind the STR tire size and the tires are the same. The limit is that the bar only affects roll and front/rear roll bias by stiffening the front. STR can affect pitch and roll with adjustments at both ends.

That could make shocks important. Looking at SoloStorm output last weekend there was one section were there were left/right transitions at the rate of 7 every 10 seconds. But what that shock should look like and if it would still be reasonable on car that is also street driven.
[/quote]


Nobody in STR is running a bar that large though. People used to stuff things like 275 wide Hoosiers on stock S2000 tires, and that's what those large bars were made for. Like you said, changing your roll bar stiffness is effectively changing your cars balance. In a perfect world, you probably wouldn't run any sway bar at all, and would tune your car with spring rates, but we happen to be in a class where that isn't possible. We put as much tire (grip) on the front of the car as possible, and then the rear end becomes loose. That's where the beefy front sway bar comes in to play. With the 245/255 combo, you are increasing front contact patch by 14% and rear by only 4%, so it's going to become loose. So you stiffen the front to balance it out. If you are pushing, you went too far, unless there are gains to be made in front grip via camber, toe, caster, or *shock*.

But on the subject of shocks, it's my personal opinion that the stock shocks are the last thing you should invest in for an S2000 in B Street. After all, a car from our region made it to 2nd in nationals last year on stock shocks with over 100,000 miles on them. On top of that, the cost of a shocks that are worth investing in, are equal to the cost of every other B Street mod combined. Until you are that fast, there are better places to spend your money.
[/quote]

A bar how big? Everyone I know in STR is running a bar similar to the Gendron or Saner in stiffness in the front.
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I was basing that off the comment that off the 2 3/8 hollow Gendron comment, and thought that was the 'Monster' bar, but checking his website, the biggest Gendron bar is only 1.375", so a confirmation on that would be good. So to clarify my statement, I don't know anybody in STR running the monster bar up front.

 

Ah ... ok, I was confused there! True, I dont know anyone that would be running a bar over 2" up front ... that would be pretty insane

Some may have the monster bar, but I doubt they would need it on full stiff. My Saner on the factory full stiff (no extra hole drilled like some do) is plenty for me so far, on some courses I have thought I would run it a notch softer when grip was low, but I have not tried it yet. You definitely want more than the standard Eibach, Whiteline, etc, but probably dont need the monster bar either.

Oh, and as I have said in other threads, for the Moddiction bar I do recommend endlinks from the user anorexicpoodle (or links made the same). They have worked much better for me than the ones that came with the Moddiction bar. Moddiction offers ones similar now but they are about $40 more per set than buying them through the user here in my experience. You could source the parts yourself, but I found (probably because he orders multiples at a time) that I could not get the parts to make them cheaper than he was asking, so I just bought them from him.

 

sorry for the misinformation, I have the 1.25" hollow bar with .25" wall thickness.

 

Remember Gendron and Karcepts are not directly comparable because the lever arm lengths are different. Brian at Karcepts posted this comparison based on twist of the bar; in both cases the arms are very stiff. https://www.s2ki.com/...st__p__23345869

Below is how much angular twist a given sway bar center section will see at one inch of shock travel:
Karcepts has a .120 wall (roughly around to 50% over stock rates), .188" wall, .250" wall, and solid 1.25" bars. The last three basically differ by one notch: Hole 6 on the .188 is roughly the same as hole 5 on the .250, and hole 6 on the .250 is roughly the same as hole 5 on the solid. I have the .188 in hole 3.

 

If you wanted, bars are available with up to a 2.43" solid center section with 1.75" 48 spine ends. The 1,25" bars are available turned down to .75" solid or .91" hollow or stepped up to stepped up in the center to 1.5". They would have to be custom ordered because the turned down/stepped up bars normally come in a 37.5" 49 spine configuration. I think ours are 36" 48 spine. I'm pretty sure this is the same for Gendron, Karcepts, and Arkeny.

A track car or a car at a multi-day event could conceivably change front and rear bars in addition to adjusting lever arm length. If they were done with out preload they wouldn't affect cross weight.

Generally though with current autocross formats where all the runs occur with maybe 10 min-20 min spacing those sorts of changes aren't practical. Has anyone made level arm length adjustments between runs?

 

Lever arm length adjustments? You mean moving the hole the endlink is mounted in?

With the karcepts and ARE bars it's no problem, I've done it between runs even with two drivers and with just me doing it with a wrench. Both front and rear bars. Gendron is significantly more difficult but I have managed it between runs before. With the gendron you have to be ready with a jack and impact wrench and helper and be practiced.

 

Also, Ankeny bars don't use splined center sections.